The present invention relates to a self-shut type lock device, and more particularly to an improved lock device comprising a movable self-shut protector overslipped in the keyhole, capable of hiding the lower tumbler segments and preventing the same from being picked through the keyhole.
There are various kinds of conventional lock devices, but their construction are almost the same in principle. Generally the common drawback is that the keyholes are all open-type and that, if peeped through the keyhole, the profile configuration of the pin tumblers will be visible from outside so that the burglar can easily imitate or utilize his self-made master keys and other tools (such as a probe or steel wire) and detect the profile configuration of the lock's opening directly in a short time and then proceed to open it stealingly, making it not anti-burglar at all.